The present invention relates to a tension member monitoring device that monitors the tension member(s) used in an elevator system and senses defects therein. A typical elevator system includes a hoistway, a hoist positioned at the uppermost part of the hoistway, an elevator car guide rail and a counterweight guide rail mounted in the hoistway, and an elevator car and a counterweight that move up and down in the hoistway along the guide rails. The car and the counterweight are connected to each other by tension member such as a wire rope or belt (regardless of whether the belt itself contains a wire rope). The tension member is driven by the hoist, which moves the car and counterweight along the guide rails.
A wire rope is typically constructed by twisting together strands made up of twisted multiple wires. Breakage, wear and the like sometimes occur in the wires or strands that constitute the rope due to the effects of frequent bending, tensile stress, abrasion, etc.
For this reason, inspection to confirm whether there are rope defects is performed periodically. In the past, visual inspection by a technician and inspection with an electromagnetic defect detector have been used together as the method of inspecting for wire breaks in the rope used for elevators.
The rope defect sensing device disclosed in Japanese Unexamined Patent Application Publication No. 2004-149317 may be given as an example using magnetic inspection. This rope defect sensing instrument comprises a sensing part that magnetically senses defects, such as wire breakage, and a signal processing part that processes signals from the sensing part. When there is a break in a wire, the magnetic field is disrupted at the location of the sensed part in the channel through which the rope passes, the disruption is captured by the sensor as a signal that is output to the signal processing part, the break location in the rope is measured, and the defect in the rope is sensed.
As another conventional example, as disclosed in Japanese Unexamined Patent Application Publication No. 2001-63938, which discloses a method in which, while an inspection device (in which a cord is stretched on a U-shaped frame) is held in a worker's hand, the device is brought directly into contact with the elevator rope while moving; vibrations transmitted from defective locations on the rope are confirmed manually by the worker himself.    Patent Citation 1: Japanese Unexamined Patent Application Publication No. 2004-149317    Patent Citation 2: Japanese Unexamined Patent Application Publication No. 2001-63938